The series was created by Ryan Murphy, Brad Falchuk, and Ian Brennan, the last of whom first conceived of Glee as a film. The three wrote all of the show's episodes for the first two seasons, and Murphy and Falchuk initially served as the show's main directors. The pilot episode was broadcast on May 19, 2009, and the first season aired from September 9, 2009, to June 8, 2010. Subsequent seasons have begun airing in September and ended in May; the fifth season is set to premiere on September 26, 2013, and a sixth season has already been commissioned.[1]Glee features on-screen performance-based musical numbers that are selected by Murphy, who aims to maintain a balance between show tunes and chart hits, and produced by Adam Anders and Peer Åström. Songs covered in the show are released through the iTunes Store during the week of broadcast, and a series of Glee albums have been released by Columbia Records. The music of Glee has been a commercial success, with over thirty-six million digital single sales and eleven million album sales worldwide through October 2011. The series' merchandise also includes DVD and Blu-ray releases, an iPad application, and karaoke games for the Wii. There were live concert tours by the show's cast after the first and second seasons completed shooting; a concert film based on the 2011 tour, Glee: The 3D Concert Movie, was produced by Murphy and Fox and directed by Kevin Tancharoen.